You could erase computer memory, but blowing up the plane won't stop them from gaining intel about the materials, mechanism, and whatnot that make up the plane. An explosion won't vaporize the airplane, just break it into smallish pieces. Those can be collected and analyzed to reconstruct most any detail about the construction of the airplane. They even do this with missiles and bombs. Even shell fragments. When artillery shells packed full of high explosives go off, their intricate fuse mechanisms are left remarkably intact.

Not my wheelhouse, but doesn't that involve packing the aircraft with explosives, and wouldn't that involve risk of blowing up if someone else shoots you? Or is there some better way to self-destruct?

I think its high-speed collision with the ground or ocean generally takes care of destroying it. Especially with no pilot attempting to keep it level and slow it down and minimize damage.

Would you go near a plane that's an electronic signal away from blowing itself up?

Even if mechanical, warplanes get combat damage, and having a system like that could make a difference between survivable and sure death.

Only good, I would think. It's pretty volatile stuff innit ? Dispersion.